This invention relates to crossbow firing or trigger mechanisms and, more specifically, to a crossbow trigger mechanism that incorporates two discrete safety features including dry fire prevention and manual on/off safety lever mechanisms.
Crossbow triggers are known that incorporate on/off type safeties that can be manipulated by the user to permit or prevent firing of an arrow. Safeties of this type act directly on the trigger without regard for whether or not an arrow has been loaded into the crossbow. In other words, on/off safeties do not prevent the dry firing of an arrow, i.e., release of a cocked bowstring with no arrow loaded into the crossbow. It is well known, however, that dry firing can cause severe damage to the crossbow itself, and prevention of dry firing is therefore highly desirable. Prior patents that describe dry fire prevention devices and/or additional safety features such as on/off devices include U.S. Pat. Nos. 4,721,092; 5,085,200; 5,596,976; 5,884,614; and 6,205,990.
There remains a need for a simple but highly reliable crossbow trigger mechanism that incorporates both a traditional on/off safety feature as well as an effective dry fire prevention feature that prevents release of the bowstring when there is no arrow in the crossbow.
In accordance with a first and preferred exemplary embodiment of this invention, a crossbow trigger mechanism is provided as a self-contained unit, supported within a trigger housing, and adapted for mounting in the stock of a crossbow. The trigger mechanism includes a pivotably mounted jaw component that incorporates a pair of bowstring retaining prongs, and that is movable between bowstring retaining and bowstring releasing positions. The trigger mechanism also includes a trigger lever assembly pivotably mounted within the housing, comprised of a trigger lever joined to a trigger block. The trigger block interacts with a sear element that is operatively interposed between the jaw component and the trigger block.
With a bowstring in the cocked position, and an arrow loaded into the crossbow, pulling and hence rotation of the trigger lever will cause pivoting motion of the sear to a position where the jaw component may pivot past the sear under the forces developed by the tensioned bowstring. In this embodiment, the jaw component incorporates a roller that rolls over an edge of the sear as the sear pivots due to movement of the trigger. The trigger lever assembly, sear and jaw component are all normally biased by spring elements to a non-firing position.
An on/off safety lever projects through the rear of the housing and is pivotably mounted in the housing for interaction with the trigger block. A safety lever actuating link is pivotably mounted on the jaw component and extends rearwardly for interaction with the safety lever during cocking of a bowstring. Specifically, movement of the jaw component to the string retaining position as the bowstring is pulled into the trigger housing, will cause the on/off safety lever, via the safety lever actuating link, to move from an xe2x80x9coffxe2x80x9d to an xe2x80x9conxe2x80x9d position where it engages the trigger block and prevents any rotation of the trigger lever assembly. When the arrow is otherwise ready for firing, the user can simply move the on/off safety lever manually to the xe2x80x9coffxe2x80x9d position, where the safety lever is disengaged from the trigger block so that the trigger can be rotated by the user to fire the arrow.
A forwardly extending dry fire prevention lever is also pivotably mounted on the jaw component, with an upper leg portion normally protruding into the area supporting an arrow before the latter is loaded into the crossbow. In this normal position, a lower leg portion of the lever is aligned with a fixed stop secured to a wall of the housing. A torsion spring mounted at the pivot location of the lever biases the lever into this normal position, which prevents the jaw component from rotating out of its bowstring retaining position. When an arrow is loaded into the crossbow, however, the dry fire prevention lever is pushed downwardly by the arrow, causing the lower leg portion to move away from the fixed housing stop, thus permitting the jaw component to move from the string retaining position to the string releasing position when the trigger is pulled.
In a second embodiment, the dry fire prevention lever is pivotally secured to the housing and arranged to engage the jaw component itself so as to prevent rotation of the latter when no arrow is loaded into the crossbow. When an arrow is loaded into the crossbow, the dry fire prevention lever pivots downwardly away from the jaw component, thereby permitting the jaw component to move to the arrow releasing position. In this embodiment, the jaw component does not incorporate a roller but, rather, is formed with an integral curved camming surface that interacts with the sear.
Accordingly, in one aspect, the invention relates to a crossbow trigger mechanism comprising a trigger housing; a jaw component pivotably mounted in the trigger housing and adapted to move between a bowstring retaining position and a bowstring releasing position; a trigger assembly pivotably mounted in the trigger housing and operatively engaged with the jaw; a safety lever pivotably mounted in the trigger housing and movable manually into and out of engagement with the trigger assembly; and a dry fire prevention lever pivotably mounted on the jaw component and comprising a first surface portion adapted and arranged to engage a stop fixed to the trigger housing when no arrow is loaded in the crossbow and thus prevent movement of the jaw component to the bowstring releasing position, and a second surface portion adapted to be engaged by an arrow such that when an arrow is loaded into the crossbow, the first surface portion is moved away from the stop to thereby permit movement of the jaw component to the bowstring releasing position.
In another aspect, the invention relates to a crossbow trigger mechanism comprising a trigger housing; a jaw component pivotably mounted in the trigger housing and adapted to move between a bowstring retaining position and a bowstring releasing position; a trigger assembly pivotably mounted in the trigger housing and operatively engaged with the jaw; and a dry fire prevention lever pivotably mounted on the jaw component comprising a first surface portion adapted and arranged to engage a stop fixed to the trigger housing when no arrow is loaded in the crossbow and thereby prevent movement of the jaw component to the bowstring releasing position, and a second surface portion adapted to be engaged by an arrow such that, when an arrow is loaded into the crossbow, the first surface portion moves away from the stop to thereby permit movement of the jaw component to the bowstring releasing position.
In still another aspect, the invention relates to a crossbow trigger mechanism comprising: a trigger housing adapted for mounting on a crossbow; a jaw component pivotably mounted in the trigger housing and adapted to move between a bowstring retaining position and a bowstring releasing position; a trigger assembly pivotably mounted in the trigger housing and operatively engaged with the jaw; a safety lever pivotably mounted in the trigger housing and movable manually into and out of engagement with the trigger assembly; and a safety lever actuating link with one end pivotally mounted on the jaw component, and an opposite end engageable with the safety lever. A dry fire prevention lever may be incorporated into the mechanism that is adapted to engage either a fixed housing stop or the jaw component itself to prevent movement of the jaw component to the bowstring release position when there is no arrow in the crossbow.
The invention will now be described in connection with the drawing figures identified below.